The present invention relates to portable antennas for use with radio equipment and particularly to foldable antennas.
The use of portable radio receivers and transmitters has increased tremendously over the last few years. In particular there has been a large growth in the use of mobile telephones. This growth has been accompanied by a decrease in the size of mobile telephones and a corresponding decrease in the size of their built-in, internal antennas. These smaller antennas can prove inadequate in extreme conditions and when the telephone is used near to or connected to computer equipment EMC problems can occur. Therefore it is often desirable to connect the mobile telephone to a separate, external, antenna. These separate antennas are normally either magnetic foot antennas or ground plane independent desk antennas. Magnetic foot antennas require large conducting, magnetic ground planes to action which makes them large and heavy. Ground plane independent antennas are often half-wave dipoles which makes them tall and heavy. In order to be stable they need a commensurably large and heavy base which makes them even larger and heavier. These antennas often need an impedance matching network which leads to signal losses and lower antenna gain. The present invention seeks to provide a portable antenna which overcomes these problems.